1. Field of the Invention
The present invention relates to a developing method for developing a desired pattern exposed to a varied photosensitive resin film such as photoresist film for use in a photolithographic process, or photosensitive polyimide resin film acting as layer insulating film, which is formed on semiconductor wafers, glass substrates for photomasks, glass substrates for liquid crystal displays, substrates for optical disks or the like. More particularly, the invention relates to a developing method and apparatus including a prewetting process carried out prior to a developing process.
2. Description of the Related Art
In a conventional method of this type, a prewetting liquid is supplied before a developer (as disclosed in Japanese Patent Publication (Unexamine) No. 1982-136646, for example).
According to this developing method, a desired pattern is exposed to a substrate surface on which photoresist film has been formed, and thereafter the prewetting liquid such as an aqueous solution having a lower developing capability than the developer used is applied to the substrate surface. Then, the developer and a rinsing liquid are successively supplied to the substrate surface to obtain the pattern thereon. The prewetting liquid is supplied to the substrate surface to modify the hydrophobic property of the surface of photoresist film to be hydrophilic so that the developer applied to the surface of photoresist film may spread uniformly over the entire film surface.
The conventional method noted above has the following disadvantage.
When the prewetting liquid is supplied to the substrate surface, bubbles of minute sizes from several micrometers to several tens of micrometers are formed in the prewetting liquid, and these bubbles adhere to the surface of photoresist film. The developer supplied to the surface of photoresist film in this condition does not reach regions of the film adjacent the bubbles. As a consequence, a defective development occurs in such regions.